Radiator sizing sanity check
@papahuhu Regarding the panel temperature: I have just carried out a check on our living room radiator - having let the Govee thermometer (claimed accuracy 0.1 degree) rest on the top of the grill for some ten minutes then taking a reading of the actual front panel just below the top edge using an infra red sensor, I found: Govee perched temperature read 28.7 and the front panel 42.7 degrees C. Regards, Toodles.
Toodles, heats his home with cold draughts and cooks food with magnets.
@toodles thanks Toodles. That looks like the most probable explanation then.
I’ve just taped mine on, I’ll give it an hour to let it all settle down, I’m not sure which bit on the device surface has the RTD on it, I’ve assumed it’s the rear cover, or perhaps it’s some fancy new electronics that I’ve not kept up with.
They’ve had a while to settle down and both read nearly exactly the same, within 0.5C.
Therefore you were right, they are providing anomalous results. So I guess they are closer to the flow temp, which makes more sense now. 👍
Heating shouldn't be this complicated. I never gave my boiler a second thought apart from a yearly service. Installers really need to learn how to do it properly or they will kill this tech.
Posted by: @papahuhuInstallers really need to learn how to do it properly or they will kill this tech.
Decades of dirt cheap North sea gas killed the competence of the heating industry in the UK. Just shove in a grossly oversized 30kW condensing boiler set to a flow temp of 75C (so it won't condense), oversized radiators, and fit TRVs to sort out the fact that you did absolutely no design at all. Customer will pay 10-20% more in running costs than they need to and be much less comfortable, but who cares because they don't know what level of comfort they could have had and the energy is cheap.
Noth Sea gas is rapidly running out and we already import 50% of our energy. If we don't shift rapidly to renewables, despot states will have us by the short and curlies. Unfortunately our hapless heating industry isn't ready, and some politicians don't recognise the economic imperative, or prefer to focus on short term arguments in order to serve their own interests. Thus it's quite possible we will become ever more dependent on despot states to the point where we have ceeded any meaningful sovereignty to their interests.
Basically we have 3.5 years (ie until the next election) to lock in renewables irrecovocably, else we are probably sunk. Unless of course the polls are wrong or the public gets real.
Welcome to the UK!
My heat pump system, largely thanks to this forum (with, I admit, some help from a degree in physics) is significantly more comfortable than the boiler it replaced (that's my wife's view not just mine). Last year it was 20% cheaper to run than gas. In the coming year it will work out roughly the same as gas because of price movements. I almost never touch the controls and have a 200 sq m 1930s house originally with solid walls and only partial fabric upgrades - hardly the classic ideal property for a heat pump! I have no controls other than those supplied by the heat pump manufacturer, and rarely touch those. There is nothing complex, just a ~8kW heat pump (7kW sticker capacity) connected directly to radiators sized to work at 45C. Basically it just works. It can be done and done well, sadly there are people in our heating industry who just haven't got a scooby.
If you want to get yours working then please continue to post.
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
this afternoon I was told whom was being sub contracted to repeat my heat loss survey next week. When I checked him up he runs a plumbing business in greater Manchester, specialising in fitting bathrooms. I have nothing against bathroom fitters, but they aren’t heating engineers. We’re screwed, looks like I’m going to be off to the SCC as my 2026 treat.
Posted by: @papahuhuthis afternoon I was told whom was being sub contracted to repeat my heat loss survey next week. When I checked him up he runs a plumbing business in greater Manchester, specialising in fitting bathrooms. I have nothing against bathroom fitters, but they aren’t heating engineers. We’re screwed, looks like I’m going to be off to the SCC as my 2026 treat.
Frankly Im not surprised. Please do read my previous post which, following 3 years on this forum and a very successful personal heat pump install, is my summary of where we are at.
The only interest your installer has at this point is to get you off his back, which is most easily done (he thinks) by showing that your installation meets the MCS rules. These, by the way, are pretty much bomb proof for installers: follow the process (which has elements of GIGO built in) and, no matter what the outcome, the installer is covered. Building regulations, fortunately, focus more on outcomes, so you may well need to invoke them if you do go to the SCC. However they require interpretation and thus robust evidence and possibly 'expert witnesses' . Expect absolutely zero support from MCS, the fact its funded by installers says all you need to know and don't be surprised if they appear as expert witnesses for the installer.
You have, I think, three options:
1. Attempt, with the help of this forum, to diagnose and fix yourself the problem that is preventing you getting warm. Its almost certainly do-able and, provided you can make accurate observations and are prepared to make changes to the configuration, pretty likely to work, probably in a couple of weeks if you put your mind to it. No guarantees of course, but given you have a well oversized heat pump its quite likely to work. This way is the quickest route to being warm that doesn't involve spending money that may not recover, and is possibly as quick as (2) - ie tjhe quickest full stop. Ultimately it will also probably achieve the best comfort for a running cost that is comparable to gas. Once the basic problem is fixed, you can look to optimise
2. Pay someone to install a 24-35kW boiler to replace the heat pump, operating almost certainly at a fixed 75C FT (or maybe 55). This is probably the most straightforward route since, by whacking up the flow temperature to 75C and using TRVs to sort out the resultant over heating, you are pretty much guaranteed to be warm, albeit not as comfortable as you could be with (1) unless your boiler installer actually understands heating and sets up weather compensation, which is highly unlikely, and if he does he he could just as easily fix up the heat pump system
3. Pursue through the SCC. This will take a long time and, if your installer chooses to fight, may require you to find 'expert witnesses', that are few and far between, to counter the fact that your installer will almost certainly be able to demonstrate that he has followed the MCS rules. Ultimately you undoubtedly have a case, but in the mean time you will remain cold and probably frustrated/annoyed.
You could combine (1) and (3) - which is what I would do if I incurred expense in getting to a system I was happy with. In principle you could combine (2) and (3) but its more challenging because you have thrown out the system. Whatever you do you need to commit and have faith to see it through.
Its sad that this is the situation, but recognising realism reduces stress and enhances decision making, at least in my experience. I sympathise deeply but ultimately only you can decide what's best for you!
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
Thank you, I appreciate the advice.
I have a couple of cards that should give me some leverage and some hope that I can persuade them to fix this. Without trying to sound like that knob head Trump, I have a close association with the best contract law firm in this region. I’m confident this trivial matter would never come to that point.
Posted by: @papahuhuThank you, I appreciate the advice.
I have a couple of cards that should give me some leverage and some hope that I can persuade them to fix this. Without trying to sound like that knob head Trump, I have a close association with the best contract law firm in this region. I’m confident this trivial matter would never come to that point.
Great then, you seem to be well sorted.
Before I 'sign off' completely I should say that many of my comments above about possible causes no longer apply, following the disclosure that the reported radiator temperatures were in fact air temperatures. This disclosure increases the likelihood that the upstairs rads are indeed undersized.
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
It was -7C here last night, the heat pump continued to behave exactly the same on/off, all it did was operate at an even higher output than I thought it was able too, upto 7 kW. Kept the homely node reference room exactly the same temp throughout the night. One observation is that it seems more smooth at high outputs in that it makes less noise. The fact that it can operate at -7 and only operate 50% of the time and continue to supply the heat demand does suggest it’s oversized. I only used 65kW yesterday, which is much better than I was expecting, but cycling my battery only got me through 3.5 of the 4 hours between the low tariff rates. I have the battery outside to reduce the fire risk and the charge rate had slowed down a little at those low temperatures, but amazing that it worked at all.
@jamespa Thanks for the help. Yes, I’m going to push for significant upsizing of all cold room rads, about 8 of them. Probably at least 50% greater output than the ones they removed in the first place. Then see what that does before doing anything else, it’s bad problem solving technique to change more than one variable at a time.
cheers
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